Approximately 20% of HIV-1 infected children have early onset and rapidly progressive disease; these infants generally die by age two years. On the other hand, 80% of HIV infected children have a delayed onset and slower progression of disease, with median age of onset exceeding six years. We here at UCSF along with others at three institutions plan to characterize 143 children 8 years or older who fit the description of slow progressors to assess the immunologic, virologic and genetic characteristics.